1. Field of the Invention
This invention relates to electrical insulators and, more particularly, to electrical insulators which are adapted to couple a metallic tubing carrying high pressure gas to a detector sensitive to stray electrical radiation.
2. Description of the Prior Art
Electrical insulator devices, including those adapted for insertion between the ends of fluid passing tubes, have been widely available in the prior art. For example, U.S. Pat. No. 1,630,657 and Italian Pat. No. 497,957 both show electrical insulator devices adapted for insertion between the ends of fluid passing tubes. U.S. Pat. No. 419,962 discloses an insulator for use between two pipes and U.S Pat. No. 1,040,971 discloses an insulator for insulating joints.
Present day technology requirements place severe design constraints on insulators which were not present in the past. For example, an infrared detector must be cooled in order to develop maximum sensitivity. The detector may be part of an infrared seeker or scanner used, for example, with helicopters or air-to-ground missles. Preferably, metal tubing is used to deliver the cooling gas to the detector. The need for an insulated coupling arises from the fact that the tubing acts like an antenna for stray electrical signals and would thus cause the detector to malfunction. However, the high pressure (up to 6000 psi), lower temperature (in the range of -423.degree. F.) characteristics of the gas place severe design constraints on the insulator to be utilized. For example, the high gas pressures utilized would cause the coupling disclosed in the aforementioned Italian patent to fail.
It would also be advantageous if the insulator, in addition to having the capability of withstanding the high pressures and low temperatures of the gas, had the additional capability of only allowing gas flow in the desired direction while preventing gas flow in the opposite direction.